How do mentions work?

You can send messages to your fellow teammates more directly with mentions. And they work just about the same way that mentions do in email, Slack, and elsewhere.

Mentions are great in a large group discussion such as a stream or project when you want to single a participant (or two or three) out. Being mentioned will send a notification to the selected user(s) and they can then reply back. 

Simply type "@" and begin typing out the name. Ledger will fill in the users (and pictures) of everybody who matches your result. Type until you see the name and once you finish your message, they'll be notified.